3. What scientific data was used to support the theory of continental drift? Identify and explain at least four pieces of evidence.

4. What were the problems with the original theory of continental drift?

5. How does the presence of ocean ridges and trenches support the theory that the continents move?

6. How does seafloor spreading support the theory that continents move?

7. Which two scientists proposed seafloor spreading? Which scientist’s proposal was confirmed by direct observations of the seafloor with submersibles?

8. How was seafloor spreading tested as a hypothesis?

9. What is Paleomagnetism? Define polar wandering and polar reversals. Why was the publication of the first paleomagnetic timescale (in 1963) so important to the seafloor spreading hypothesis?

10. How does the global distribution of earthquakes support the theory?

11. How does GPS help us study Continental Drift?

12. In your own words, state the theory of plate tectonics.

13. How does the development of the theory of plate tectonics illustrate the changing nature of scientific knowledge?

14. How was the scientific method used to establish the theory of plate tectonics?

15. What is a theory? Can theories change? What has to happen to a scientific explanation for it to become a theory?

16. What was Pangea? How does the theory of Plate Tectonics lead modern scientists to believe that the Earth will experience a second Pangea (in ~250ma)?

17. List the Earth’s layers, their composition, and their approximate depth from the surface. How do we gain a better understanding of how Plate Tectonics works by studying the differing mechanical strengths of each layer?

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...﻿PlateTectonics
First proposed by Alfred Wegener the meteorologist, the theory of continental drift supports the belief that the Earth's continents once were a single land mass. This land mass, which was named ‘Pangaea’, broke up, and its various parts drifted away from one another. Known as the Jigsaw fit, where countries fitted together but broke apart from Pangaea, shown by South America fitting into Africa.
There is a lot of evidence that supports the theory, including paleomagnetism, sea floor spreading, glacial movements as well as fossils being found on different land masses which are similar.
Firstly, fossils from dinosaurs are found on widely separated lands, for example, the Rapetosaurus has been found in both Madagascar and India which are vastly separated by the Indian Ocean, this shows that these land masses must have been joined together at some stage and drifted away by continental drift.
Harry Hess and Fred Vine both discovered sea-floor spreading which is the process in which the ocean floor is extended when two plates move apart. As the plates move apart, the rocks break and form a crack between the plates. Earthquakes occur along the plate boundary. Magma rises through the cracks and seeps out onto the ocean floor like a long, thin, undersea Volcano.
As magma meets the water, it cools and solidifies, adding to the edges of the sideways-moving...

...﻿PlateTectonics
Ever since the beginning on time, Humans believed the ground is solid and immobile. But this is not true whatsoever. The Earth is every-changing and continually in motion. The stability of the Earth is not at all what we think it is. Thinking about the rotational axis of the Earth, and possibly of what the Earth may become at a certain point in time, has a great influence on understanding all aspects of living things, either in the past, present, or future. The study of Platetectonics is accredited to most of the creations of Mountain Ranges, the drifting of continents, earthquakes, and volcanic activity. Platetectonics and mountains also play a big part in the geological features of our planet or any planet for that matter.
Geophysics, which studies the physics of the Earth, has led to many important findings about the Earth and how it is made. Seismologic studies of planet Earth have revealed new information about the inside of the Earth that has helped to give new openings in understanding platetectonics. The Earth is made of several significant layers. Each one of these layers has its own properties. The crust is the outermost layer of the Earth. The crust is made up of the oceans and continents. The crust has a fluctuating thickness, being thirty to seventy-five kilometres thick in the continents and ten to fifteen kilometres thick...

...﻿Geology 101 Lab: PlateTectonics
Goals of this lab:
-to learn about types of Plate Boundaries
-to learn about Plate Boundary Interactions
-to familiarize yourself with the PlateTectonic Map of the World
-to understand and familiarize yourself with past Plate Movement and the
supercontinent Pangea
-to understand the Hot Spots of Hawaii and Yellowstone
Part 1. Types ofPlate Boundaries
There are 3 types of plate boundaries and a fourth called a “plate boundary zone” in
which the type of plate boundary is not clearly defined. Go to the website:
http://pubs.usgs.gov/publications/text/understanding.html
and learn about the three types of plate boundaries and answer the questions below.
1. What are the three types of plate boundaries?
Transform, Divergent, Convergent
2. What directions do the plates move relative to one another in a divergent plate
boundary?
They are pulling away from each other.
2. What is a spreading center and what is made at one?
Mid ocean range or submerged mountain range. Volcanos are made here.
3. Name one spreading center (or divergent plate boundary).
Mid-Atlantic Ridge.
4. What are the three types of convergent plate boundaries?
Oceanic-continental convergence, Oceanic-oceanic convergence,...

...Continental Drift and PlateTectonics Theory (Part 1a)
Introduction: The Beginning of the “Continental Drift Theory”
In the middle of the eighteenth century, James Hutton proposed a theory, uniformitarianism; “the present is the key to the past”. It held that processes such as geologic forces- gradual and catastrophic-occurring in the present were the same that operated in the past. (Matt Rosenberg, 2004) This theory coincides with the theory of Continental Drift that was first proposed by Abraham Ortelius in December 1596, who suggested that North, South America, Africa and Eurasia were once connected but had been torn apart by earthquakes and floods. He also discovered that the coasts of the eastern part of South America and the western coasts of Africa fit together like a jigsaw puzzle and this fit becomes especially prominent as the edges of the continental shelves have similar shapes and thus, appear to be once fitted together. (Figure 1.1 and Figure 1.2)
The similarity of southern continents’ geological formations had led Roberto Mantovani to speculate that all continents had once been a supercontinent and was smaller in its volume than it is now. Through volcanic activity, fissures are created in the crust causing this continent to break apart. However, this theory, known as the Expanding Earth Theory has since been proven incorrect.
The Theory of Continental Drift
In 1912, The Theory of Continental Drift was intensively developed...

...theory of platetectonics explains how forces within the planet create landforms. This theory views Earth’s crust as divided into more than a dozen, rigid, slow-moving plates. Some plates are as large as a quarter of the planet, but others are only a few hundred miles across. The plates slowly move across the upper mantle, usually less than an inch per year.
Scientists use the theory of platetectonics to explain the long history of Earth’s surface. They believe that about a few million years ago, all the continents that we have now today were part of one super continental called Pangaea. Pangaea then broke into two smaller supercontinents called Gandwana and Laurasia. These two then broke into the modern continents we have today. The theory of platetectonics helps explain the fit between the African coastlines and South America. Rock formations that match up across boundaries provide more evidence. The theory also helps geographers understand the origins of mountains and the landforms of the ocean floor.
The earth has a vast range of landscapes including the lay landscapes of Polar Regions, mountainous landscapes, densely forested or wooded landscapes including past bereal forests and tropical rainforests, and agricultural landscapes and tropical regions.
My particular interest in this case study is to find out how these plate...

...﻿Assess the strength of the relationship between tectonic processes and major landforms on the earth’s surface.
Tectonic processes have been responsible for the major landforms across the Earth’s surface. These processes are controlled by the convection currents rising from the Earth’s mantle.
Firstly, one place where tectonic activity occurs is at oceanic to oceanic constructive plate boundaries. Here two plates diverge or move away from each other, pushed apart by huge convection currents In the earth’s mantle. These convection currents are initiated by heat energy produced from radioactive decay in the earth’s core. As the convection currents move the plates away from each other, there is a weaker zone in the crust and an increase in heat near the surface. The hotter, expanded crust forms a ridge. Magma rises up from the mantle in the gap. The lava cools, solidifies and forms a chain of volcanic mountains thousands of miles long down the middle of the ocean eg. Atlantic. There are transform faults at right angles to the ridge. The movement of these faults causes rift valleys to occur. Examples of these landforms created by constructive plate margins are the Mid Atlantic Ridge (MIR) , and the Great African rift valley (GARV). The MIR is the result of the North American plate and Eurasian plate diverging in the middle of the Atlantic...

...“Evaluate how platetectonics theory helps our understanding of the distribution of seismic and volcanic events” (40 marks)
The theory of platetectonics was first introduced by Alfred Wegener in 1912. He observed the continents an could see they interlock like a jig saw puzzle, for example the West African Coastline fits snugly into the South American coastline, he suggested that at one point in time there was only one giant continent called “Pangea”. Later evidence was found that proved this theory as the fossil remains of a dinosaur, the Mesosaurous was found along the coast of Brazil as well as along the coastline of Gabon, also fossilised pollen species and rock sediments were both found along these coastlines. This further demonstrated that Wegener’s theory was accurate.
Wegener’s ideas were proved further right and built upon our understanding of tectonic activities. Sea floor spreading was discovered showing that rock is being created and destroyed, this lead us to believe that plates and plate boundaries existed. The mid-Atlantic ridge is a constructive plate boundary where by the Eurasian and North American plates are moving apart, this allows magma to rise creating new plate material. This has created the island of Iceland which in itself has rift valleys which are evidence so support the plates are moving...

...Platetectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός "pertaining to building")[1] is a scientific theory that describes the large-scale motions of Earth's lithosphere. The model builds on the concepts of continental drift, developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were developed in the late 1950s and early 1960s.
The lithosphere is broken up into tectonicplates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary: convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.[2]
Tectonicplates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This...